MPEG-4概述

从ISO/IEC14496的第一部分MPEG-4系统的体系结构出发,分别对MPEG-4标准中提供的主要工具进行了技术描述,包括对象描述框架、系统解码器模型(SDM)和传输多媒体集成框架(DMIF)、场景的二进制描述(BIFS)、同步层、视频对象和音频对象编码等.最后对MPEG-4系统的特性做出了小结并探讨了该标准的应用前景.     

MPEG-4: a multimedia standard for the third millennium. 2

MPEG-4 defines a multimedia system for interoperable communication of complex scenes containing audio, video, synthetic audio, and graphics material. In part 1 of this two-part article (Battista et al., 1999) we provided a comprehensive overview of the technical elements. In part 2 we describe an application scenario based on digital satellite television broadcasting, discuss the standard's envisaged evolution, and compare it to other activities in forums addressing multimedia specifications     

MPEG-4: a multimedia compression standard for interactiveapplications and services

The Moving Pictures Experts Group (MPEG), which produced the MPEG-1 and MPEG-2 video and audio compression standards, is developing the MPEG-4 standard. MPEG-4 targets interactive multimedia applications and will become a standard in 1999. As well as an increased compression efficiency, MPEG-4 will also offer content-based functionality, i.e. the possibility of accessing and manipulating individual objects in the picture. Furthermore, MPEG-4 will offer possibilities for efficient video storage and for transmission over poor audio and video channels at bit rates between 5 kbit/s and 4 Mbit/s. This paper gives an overview of the state of the art of MPEG-4 development, concentrating especially on video content-based functionality, which is so important for interactive applications     

MPEG digital audio coding

The Moving Pictures Expert Group (MPEG) within the International Organization of Standardization (ISO) has developed a series of audio-visual standards known as MFEG-1 and MPEG-2. These audio-coding standards are the first international standards in the field of high-quality digital audio compression. MPEG-1 covers coding of stereophonic audio signals at high sampling rates aiming at transparent quality, whereas MPEG-2 also offers stereophonic audio coding at lower sampling rates. In addition, MPEG-2 introduces multichannel coding with and without backwards compatibility to MPEG-1 to provide an improved acoustical image for audio-only applications and for enhanced television and video-conferencing systems. MPEG-2 audio coding without backwards compatibility, called IMPEG-2 Advanced Audio Coding (AAC), offers the highest compression rates. Typical application areas for MPEG-based digital audio are in the fields of audio production, program distribution and exchange, digital sound broadcasting, digital storage, and various multimedia applications. We describe in some detail the key technologies and main features of MPEG-1 and MPEG-2 audio coders. We also present the MPEG-4 standard and discuss some of the typical applications for MPEG audio compression     

MPEG-7多媒体信息检索标准分析

对MPEG-7产品特点和功能作了简单描述。重点研究了MPEG-7视频技术中最重要的可视特征和视觉描述,这部分是多媒体视频和音频信息的重要描述部分,是多媒体视频、音频信息的具体表示形式。通过对这些信息的特点进行具体的描述和表示能够快速有效的查询和浏览多媒体图画、图形、N维模型、音频、演讲、视频等用户感兴趣的信息。     

Instruction Set Extensions for MPEG-4 Video

This paper describes instruction set extensions for the acceleration of MPEG-4 algorithms on programmable (RISC-) CPUs. MPEG-4 standardizes audio and video compression schemes for a variety of bit rates and scenarios. As MPEG-4 targets a much broader range of different applications than previously defined hybrid video coding standards like H.263 or MPEG-2, it employs a much higher number of different algorithms and coding modes. Therefore, MPEG-4 implementations will require a more software-oriented approach to be efficient. However, the total computational load for an optimized implementation of an MPEG-4 video codec is expected to exceed the performance levels of today's multimedia signal processors, making further hardware acceleration a necessity. For that purpose, we propose a number of instruction set extensions that add function-specific blocks to the data path of a CPU. These dedicated modules are highly adapted to the most computation-intensive processing schemes of MPEG-4, such as DCT, motion compensation, padding, shape coding, or bitstream parsing. The increased functionality of basic instructions results in a significant speed-up over standard RISC instruction sets, thus making MPEG-4 implementations feasible on programmable processor platforms. Possible target architectures include VLIW multimedia processors, MIMD-style multiprocessors, or coprocessor architectures     

Fast MPEG-4 Motion Estimation: Processor Based and Flexible VLSI Implementations

MPEG-4 is a new multimedia standard combining interactivity, object-based natural and synthetic digital video, audio and computer-graphics. For the implementation of the video part of the MPEG-4 standard a high degree of flexibility is required, where the motion estimation requires the highest part of the computational power. Therefore, in this paper fast algorithms for MPEG-4 motion estimation are evaluated in terms of visual quality and computational power requirements for processor based implementations. Due to the object-based nature of MPEG-4 also new VLSI architectures for MPEG-4 motion estimation are required. Therefore known motion estimation architectures are evaluated on their capability of being modified for MPEG-4 support. Based on this evaluation a new dedicated, but flexible MPEG-4 motion estimation architecture targeted for low-power handheld applications is presented, which resulted to be advantageous to processor based implementations by magnitudes of order.     

网络化多媒体实时监控系统的应用研究

采用MPEG－1编码解码国际标准和TCP／IP网络协议,在网络环境下,实现视音频信息和控制数据的网上传输。介绍了网络化多媒体实时监控系统的的构成、工作原理和功能特点,并对视音频实时编码技术和网络编程技术进行了详细探讨。     

运用VLC媒体播放器增加HDTV播出频道的实践

VLC是一个开放源代码的、跨平台的多媒体播放器,它可以播放多种音频和视频格式(MPEG-1、MPEG-2、MPEG-4、D ix、MP3、Ogg等以及DVD、VCD、CD音频以及各种流媒体协议),VLC同时也具有转码能力(UDP unicast和multicas、tHTTP等),主要为宽带网络设计的流媒体服务器使用。基于上述软件,结合拥有G igabitEthernet I/O板卡的统计复用网关DM6400、复用/加扰/调制器BN G6104和播发服务器、HDTV机顶盒,试验播出2个HDTV频道。     

基于MPEG-4网络视频服务器的研制

针对数字网络视频监控系统的需求,研制了一种基于MPEG-4网络视频服务器。采用AT91RM9200芯片作为嵌入式CPU芯片,GO7007SB芯片作为MPEG-4硬件压缩芯片。从系统的硬件设计和软件设计2部分介绍了系统的音视频采集、压缩、存储、传输及系统控制等方面设计。实验证明,该系统性能稳定、使用灵活,在视频监控、视频会议等各个领域中将会有广泛的应用前景。     

MPEG-4 natural audio coding

MPEG-4 audio represents a new kind of audio coding standard. Unlike its predecessors, MPEG-1 and MPEG-2 high-quality audio coding, and unlike the speech coding standards which have been completed by the ITU-T, it describes not a single or small set of highly efficient compression schemes but a complete toolbox to do everything from low bit-rate speech coding to high-quality audio coding or music synthesis. The natural coding part within MPEG-4 audio describes traditional type speech and high-quality audio coding algorithms and their combination to enable new functionalities like scalability (hierarchical coding) across the boundaries of coding algorithms. This paper gives an overview of the basic algorithms and how they can be combined.     

基于嵌入式Linux与S3C2410平台的视频采集

针对数字网络视频监控系统的需求,设计一种基于MPEG-4网络视频服务器。使用基于MPG440的MPEG-4实时视频压缩卡压缩采集到的音视频数据,利用循环队列实现音视频数据的压缩,同时运用多线程技术以及传输机制解决网络数据的传输,从而有效克制了画面不清晰、音视频不同步、马赛克等现象,保证客户监看时音视频实时性和同步性。经过实验证明,该方案经济高效,可应用在多种需要音视频监控的场合。     

Architecture and design of NX-2700: a programmable single-chip HDTVall-format-decode-and-display processor

This paper describes the architecture, functionality, and design of NX-2700, a digital television and media processor chip from Philips Semiconductors. The NX-2700 is the second generation of an architectural family of programmable multimedia processors targeted at the digital television (DTV) markets, including the United States Advanced Television Systems Committee (ATSC) DTV-standard-based applications. The chip not only supports all of the 18 ATSC formats from standard-definition to wide-angle, high-definition video, but has also the power to handle high-definition television (HDTV) video and audio source decoding (high-level MPEG-5 AC-3 and ProLogic audio, closed captioning, etc.) as well as the flexibility to process advanced interactive services. NX-2700 is a programmable processor with a very powerful, general-purpose very long instruction word (VLIW) central processing unit (CPU) core that implements many nontrivial multimedia algorithms, coordinates all on-chip activities, and runs a small real-time operating system. The CPU core, aided by an array of peripheral devices (multimedia coprocessors and input-output units) and high-performance buses, facilitates concurrent processing of audio, video, graphics, and communication-data     

AAC:21世纪音频编码的主流

数字音频编码技术无论对多媒体通信、多媒体广播、消费类电子都有其重要性。首先简要地回顾了数字音频编码技术的发展过程,然后介绍了包括MPEG音频,MP3,AC-3,ATRAC,PAC在内的8种现行商用数字音频编码系统,并作了特征比较,作为重点、详细地叙述了MPEG-2AAC的算法和特点。介绍了ITU-R有关高质量音频编码主观评价的方法,给出了AAC,PAC,MP3,AC-3音质评分表,评分显示在相同低数码率时AAC具有最好的音质,达到了ITU-R的有关规定。最后简要介绍了AAC的实现。     

嵌入式MPEG-4网络视频流媒体服务器的设计与实现

详细介绍了一套基于MPEG-4压缩的嵌入式网络流媒体采集、传输、控制系统.嵌入式CPU采用S3C2410B,嵌入式操作系统采用嵌入式Linux操作系统,MPEG-4视频压缩芯片采用MPEG-4硬压缩芯片WIS GO7007B.     

MPEG-Past and Future

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基于MPEG-2TS的多路音频存储播放系统设计

设计了一种多路音频自动存储播放系统,该系统接收12路AES／EBU数字音频信号,采用MPEG－2TS生成音频复用TS流,并通过网络传输到指定的硬盘存储。根据播放指令,该系统可选择还原任意一路任意时段的数字音频,并送至播放单元播出。系统仿真和板上验证结果表明,所设计的系统实现了预定的功能。     

MPEG-4 multimedia for our time

The MPEG-4 standard explores every possibility of the digital environment. Recorded images and sounds co-exist with their computer-generated counterparts, a new language for sound promises compact-disk quality at extremely low data rates; and the multimedia content could even adjust itself to suit the transmission rate and quality. Possibly the greatest of the advances made by MPEG-4 is that viewers and listeners need no longer be passive. The height of “interactivity” in audiovisual systems today is the users ability merely to stop or start a video in progress. MPEG-4 is completely different: it allows the user to interact with objects within the scene, whether they derive from so-called real sources, such as moving video, or from synthetic sources, such as computer-aided design output or computer-generated cartoons. Authors of content can give users the power to modify scenes by deleting, adding, or repositioning objects, or to alter the behavior of the objects. Perhaps the most immediate need for MPEG-4 is defensive. It supplies tools with which to create uniform (and top-quality) audio and video encoders and decoders on the Internet, preempting what may become an unmanageable tangle of proprietary formats. In addition to the Internet, the standard is also designed for low bit-rate communications devices, which are usually wireless